Expression of Krüppel-like factor 5 in human gastric carcinomas

Purpose: Krüppel-like factor 5 (KLF5) is a zinc finger transcription factor, which has recently attracted attention because of its important regulatory activities linked to diverse functions such as cell growth, proliferation, differentiation, and tumorigenesis in a number of systems. However, its expression in human gastric cancer has not been described previously. In this study, we investigated the expression profile of KLF5 and the relationship between its clinicopathologic features and expression in gastric carcinomas. Methods: Tissues were obtained from 247 gastric carcinoma patients who underwent curative gastrectomy (R0 resection) at the Department of Surgery, Seoul National University Hospital from January 1995 to June 1995, and these tissues were arranged in tissue array blocks. KLF5 expression was analyzed by immunohistochemical staining using anti-BTEB2 mouse monoclonal antibodies (Santa Cruz Biotechnology Inc., Santa Cruz, CA, USA). Results: Overall KLF5 was found to be expressed in 45.7% (113/247) of tumor tissues. Moreover, its expression rate was significantly high in early-staged gastric cancer (63.2 vs. 38.0%, p < 0.001), in gastric cancer without lymph node metastasis (54.0 vs. 40.1%, p = 0.04), and in tumors <5 cm in size (53.0 vs. 38.1%, p = 0.02). The 5-year survival rate of patients with KLF5-positive tumors was higher than those of patients with KLF5-negative tumors, although this was not statistically significant (74.7 vs. 62.2%, p = 0.057). Conclusion: KLF5 expression rate was high in early-staged gastric cancer, in small gastric cancer tissues and in gastric cancer without lymph node metastasis. By univariate analysis, its expression was found to favor survival after surgery. Our study describes for the first time the expression profile of KLF5 in a large number of human gastric cancer tissues and suggests consistent results shown in many recent studies that reduction of KLF5 expression occurs in many types of human tumor.